In a power conversion device such as an in-car AC/DC converter, a substrate on which a semiconductor switching element for power conversion is mounted is arranged in a chassis. The semiconductor switching element is a heat-generating element, and thus needs to be efficiently cooled.
PTL 1 describes a heat releasing structure in which a protruding part for heat conduction is integrally formed on an inner surface of a case made of a heat conductive resin, and a heat-generating element mounted on a substrate is directly in contact with the protruding part for heat conduction or the heat-generating element is in contact with the protruding part for heat conduction via a heat-releasing member, so that heat of the heat-generating element is released to the case through the protruding part for heat conduction and cooling of the heat-generating element is efficiently performed.